weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 12:56 pm

I have a henderson loader which has cylinders which were recently rebuilt by a hydraulic shop. It has its' own hydraulic pump seperate from the standard cub touch control hydraulics. I don't think I ever cycled the system properly as it has been pretty weak since I reinstalled the cylinders. It would hesitate before lifting and even once lifting it was not able to lift much of a load. I thought the fluid level was low so I added more; I think I must have over filled it because when I downward pressure with the bucket, fluid would pour out of the vent cap. I am guessing the weak lift is due to air in the line, but I don't have much experience with hydraulics. I could use tips on how to cycle the pump to get the air out and any other advice.

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 1:32 pm

Typically, hydraulic systems like front end loaders, need to be cycled fully up, fully down, many times in a row, just to bleed out air. It does sound like you have over filled it, but that will typically not hurt anything since the extra just pukes out the vent. On most loaders, the reservoir is just a little bigger than what is needed for the cylinders to be fully extended.

If the pump is driven from the PTO (as I'm guessing) your engine speed will also effect the pump speed, therefore, it is probably designed to operate correctly with the engine running at wide open throttle, or at least 2/3 throttle. The henderson loaders are not very fast to begin with, but it should be able to lift several hundred pounds pretty easily.

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 2:21 pm

When dealing with a loader that uses one-way cylinders (power up, gravity down) ALWAYS fill the reservoir with the loader completely lowered to the ground. Otherwise you will get overflow, as you found out.

Any pump powered by the tractor engine will vary in speed and strength based on how fast the engine is running. If you can't lift anything with the tractor running wide open, then the pump is probably shot.

Take Bill's advice above, run the loader all the way up and down several times to work out the air. If the loader stops before it goes all the way up, you've run out of oil. Drop it back down and top off the reservoir.

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 6:13 pm

The pump is attached by belt to the engine. Even at full throttle in neutral, it is very weak. Probably the pump. Not sure what to do about that... pump is visible in this thread viewtopic.php?f=1&t=62306&p=514913#p514913Any thoughts on converting it to run off of the touch control?

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 7:47 pm

My Henderson doesn't have an outboard hydraulic pump. It gets plumbed to the Touch Control. So you should be able to plumb yours through the Touch Control as well. Remember that you will need to make sure that the reservoir is filled. Pay attention to what Matt mentioned... I think that would be important. I would probably plumb it similar to the way I plumbed the splitter project.

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 10:12 pm

The control lever assembly has a safety valve in it that may be set too low, or the spring may be weak broken.

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 10:40 pm

Thanks to all. Plenty of things to check into.

Re: weak loader- cycling hydraulic pump?

Thu Nov 08, 2012 10:46 pm

ozimmerman wrote:The pump is attached by belt to the engine. Even at full throttle in neutral, it is very weak. Probably the pump. Not sure what to do about that.

Conduct a pressure test on pump. Guessing, you will need 1200 psi or hopefully much more out of the pump.

See if there is some sort of identification on the pump or system. If there is, perhaps you can determine it's capabilities.

Re: weak loader- cycling hydraulic pump?

Tue Nov 13, 2012 1:05 pm

Well, it was a simple fix. The belt was too loose. It was tight enough for the tractor to run, but as soon as the loader had any weight on it, the belt would slip at the hydraulic pulley. Adjusted the pump to tighten the belt and it works fine. Still might look into plumbing it to the touch control, but it isn't critical at this point.

Re: weak loader- cycling hydraulic pump?

Tue Nov 13, 2012 2:11 pm

Glad you got it fixed and that it really was only a minor issue. Thanks to for reporting back on what the problem was Enjoy playing with your loader

Re: weak loader- cycling hydraulic pump?

Tue Nov 13, 2012 3:02 pm

Ah, the Achilles heel of belt-driven hydraulic systems.

Yes, you can power your loader off the touch control. It requires a bypass block, some plumbing, and an external reservoir connected to the fill pipe of the TC unit. Lots of info on this modification on this forum.